As more and more research results come to light, one thing is becoming clear: your gut has far more to do with your overall physical and emotional health than any of us previously realized. When your gut is not healthy, you can experience all kinds of problems.
A Quick Overview of Your Digestive System
In order to understand the importance of the gut, you need to know how the digestive system works in general.
The moment you put food into your mouth and start chewing, enzymes in your saliva begin the process of breaking down the proteins, sugars, and fats in the food. This process continues when you swallow and the food moves down into your stomach.
In the stomach, enzymes in the food itself, enzymes that are produced by your pancreas, and hydrochloric acid further break down the food.
After about four hours, the food has been reduced to a sludgy mush in the stomach. As the sludge moves into the small intestine, we now refer to it as chyme (pronounced “kime”). The chyme mixes with yet more enzymes and now some bile to break down the sludge into tiny particles that your body can use for energy. The walls of the small intestine, which contain millions of little fingers called “villi” and “microvilli,” begin to absorb the nutrients from the chyme and move them into the bloodstream, where they are distributed to all parts of the body.
The chyme, now drained of immediate nutrients, moves into the colon, the last stretch of the digestive system. Here in the colon, water from the chyme is absorbed. Also in the colon live the bulk of the beneficial microbes that line the entire digestive tract, and these microbes eat the leftovers, such as fiber, that couldn’t be utilized by the small intestine.
As the microbes in the microbiome consume these remnants, they do several things:
They produce a fermented byproduct in the form of short-chain fatty acids that creates the vital mucus lining of the gut
They control metabolism of the calories you eat
They interact with your body’s hormones to give you the signal that you are full or hungry
They manufacture important vitamins like the B vitamins (used for energy) and Vitamin K (necessary for proper blood clotting)
They interact with both your immune and nervous systems.
After the water from the sludge has been absorbed and all the microbes have consumed all the leftovers that they want, the sludge becomes compacted and solid and is called “feces.” The feces is moved into the rectum and is eliminated when you have a bowel movement.
Healthy Gut vs. Unhealthy Gut
A healthy gut is able to do two main things: 1) absorb nutrients from the food you eat, and 2) support the beneficial microbes that create more vital nutrients that support overall health.
A healthy gut is teeming with trillions of the right types of microbes, including bacteria, fungi, and archaea. When you eat the right types of foods to support them, these microbes are in balance and perform vital functions for health. If you have a healthy gut, you probably feel energized, sleep well, are at a healthy weight, and are able to deal with stress in positive ways.
An unhealthy gut, on the other hand, starts to resemble a no-man’s-land of dry, mucus-free gut lining and cracks that allow microscopic particles of food to enter the bloodstream and cause inflammation. What’s more, the balance of microbes has become off-kilter, allowing some types to flourish over others, and for the diversity of the microbe population to diminish sharply. Those with unhealthy guts tend to crave sugary and junk foods, become depressed more often, and gain weight even when trying to control calorie intake.
Obesity: a Study of Mouse Populations and Their Guts
Fascinating studies done on human microbiota provide evidence that the more diverse the population of microbes in our guts, the less likely we are to develop obesity.
One study run by Jeffrey Gordon of Washington University in St. Louis compared the gut microbes of pairs of human twins, one of whom was overweight and one of whom was thin. The study concluded that those twins who were a healthy weight had a far greater diversity of gut microbes than those twins who were overweight.
Gordon conducted another study on mice in order to determine the cause and effect of a vastly diverse microbiome. In this study, genetically identical baby rodents were raised in a germ-free environment. These mice were then given intestinal microbes from the overweight human twins and the lean twins, after which they were fed the same diet in equal amounts. The mice who had the microbes from the obese twins gained weight while the mice with the thin twins’ microbes stayed lean.
Gordon concluded that the lack of diversity in the overweight twin’s guts created gaps in the roles that specific microbes play in the gut. These gaps mean that certain roles and jobs do not get filled, leading to issues such as obesity as well as asthma, eczema, and celiac disease, among others. [Read more about Jeffrey Gordon’s studies here.]
Creating a Diverse Gut Microbe Population
The Western diet is one of the least helpful diets a person can consume if you want to populate your gut with a diverse population of microbes. The high fat, high sugar, low fiber aspects of our diet are actually perfect for ruining the diversity of our gut microbiomes.
While we are still learning all the ways in which the microbiome affects human health, it seems logical to pursue a better diet in the meantime, as a diverse microbe population seems to support healthy weight and better health overall. High fiber, low-glycemic foods such as raw and lightly cooked vegetables, fruits, grains, legumes, nuts, seeds, and lean meats deliver diverse microbes to the gut. Fermented foods also provide amazing beneficial bacteria. Refined foods and junk foods decimate the gut microbe diversity and cause leaky gut syndrome.
In your quest toward a healthier microbiome, you can also include probiotic supplements that will ramp up the number and diversity of microbes that line your intestinal walls.
In future posts, we’ll explore the microbiome in more detail as well as prebiotic and probiotic foods that help build a diverse microbial collection.